Method of making valves for explosion engines



April 1933- A. FERRANDO ET AL 1,904,430

METHOD OF MAKING VALVES -FOR EXPLOSION ENGINES Filed March 2, 1929 Fig. 1 2 a I a l 10.

V- L. Fig.3 j

l V 1/ W3 Fig,5

Patented Apro 18, 1933 y m are.

AMEDEO FERBANDG AND INO ZANZI, OF IVBEA, ITALY, ASSIGNORS T0 DI'ITA GIOVANNI ZANZI, 0E IVEEA, ITALY METHQD 0? "Mi ENG VALVES FOB LOSIOfi' ENGINES Application filed March 2, 1939, Serial No. 348,929, and in Italy April 4, 1928.

The valves for explosion engines esently in use are made in one piece of high-grade material as would be strictly necessary only for the valve head, this material being generally steel containing a high percentage of nickel or nickel-chrome, which is very hard, requires time and power for the mechanical treatment which meets with considerable difficulties at high temperatures as required by upsetting and pressing, as the material easily loses its properties if the temperature exceeds certain narrow limits necessary for obtaining good forging results.

Attempts have been made to reduce the high cost of valves entailed by the use of the high-grade material for the whole valve and by the expenditure of time and money in manufacturing the valves by upsetting on special electric machines from a high-grade steel bar, which is heated through the J oules eifect and jolted so as to form an enlarge ment out of which the valve head is pressed. By this method the metal often burns owing to the excessive local heat in the most dangerous point for the breakage of the valve, i. e. in the connection between head and stem. The consequence is a great deal of waste without any guarantee that the metal has not lost its properties owing to the excessive, or sometimes unsufiicient heating during upsetting as it is practically impossible to efit'ect a reliable control of the working temperature.

By the use of this invention the above mentioned drawbacks are obviated and valves the valve head is made of a material other 1 than that constituting the stem. We make the valve head of a high-grade material and employ for the stem 2. less expensive, hard and strong material, as suficient for the work of the stem, which is limited exclusively to sliding in the guide member. I

Another object of the invention is to force and enlarge the stem end into the head, which ensures a'perfect connection of the two materials by hot pressing.

According to our process the perfe'ctly polished end of the bar adapted to form the stem is introduced into a blind bottom cylindrical recess of corresponding size, formed on a smaIl high-grade steel cylinder adapted to form the valve head.

The bar end which has been forced into the cylinder is then heated until this later reaches a suitable temperature, generilly equal to the temperature beingthe lower 1: mit for a good forging of the material of which the cylinder is made. The parts thus attached together are then brought under a press and the finished head of the desired form is obtained by a single pressing operation, after which the valve has just to bt finished, i. e. the seat and stem are ground and a slot is cut at the stem end for fitting in the cotter.

As stem metal we use e. g. a drawn steel bar with a small percentage of nickel, while we employ as head metal a steel bar containing a high percentage of nickel or nickelchrome and having a larger diameter, which we cut into cylinders of the desire l length, into a blind bottom recess whereof we force the stem end.

During hot pressing the fibres of the cylinder metal extend and come parallel to the outer surfaces of the valve head i? the portion of this latter which undergoes the higher stresses and the stem end fitted in! o the cyltions of this latter so that the connection of the two metals in the joint is absolutely conto o in di erent forms of joints between head and stem, according to requirements, form and use of the valve to be manufactured.

The accompanying drawing shows by way of example, some constructional forms of the object 0 this invention.

Figures 1 and 2 show the two parts adapted to form the valve head and stem, respectively, before and after pressing.

Figures 3 and 4 are similar views of a modified construction.

Figures 5 and 6 show a further modified form.

The valve heads shown in Figures 2, 4' and 6 are pressed in. their ultimate form, after which only grinding of the seat surface is required. 7

1 denotes the rod adapted to form the BE varyin the cylinder size it-is possible I projection, in fitting in said borea cylindrical stem of lower grade metal having in its end surface a conical cavity correspondin to the conical projection of the bottom 0 the cylinder bore, in heating. said cylinder and said stem and upsettin simultaneously said cylinder and the end 0 said stem to expand the stem material radially in the form of a" flange of substantial thickness enclosed in a casing of uniform thickness constitutin the vs vs head.

lin testimony that we claim the foregoing as our invention, we have si ed our names.

AMEDEU ERRANDU. 4 ALBINQ .ZANZK.

valve stem and the end 1" of which is fitted into a recess of the same size on the highgrade steel cylinder 2.

The cylinder 2 is conveniently cut from a bar of suitable diameter.

By hot pressing the parts take the form 7 shown, in sectional view in Figure 2; the

cylinder 2 becomes the head 2a and the stem end 1' becomes the enlargement 1a clam d in the valve head, The connecting sur ace between the two parts ends almost perpene dicularly to the joint between head and stem 1 and there is no discontinuity in this point shown in in%the valve structure.

during workin as a sort of welding has taken place between both materials.

According to the modified construction shown in Figures 3 and 4, in order to obtain on the up er valve surface a recess 2a, we make the ottom 'of'the recess on the cylinder 2 (Fig. 3) of a conical form corresponding to that of a recess 1" on the end 1. of the stem 1.

Accordin to the modified construction igures 5 and" 6, thecylinder 2 is provided with a, rounded bottom 2', while the blind bottom on which the valve stem 1 is fitted ends by a conical recessed portion 2".

In this casethe pressin operation takes place under particularly 'avourable conditions and the cylinder metal is upset downwards and spreads on a larger zone reinforcy varying the form of the cylinder 2 and its initial joint with the stem it is ossible toobtain after pressing an ultimate oint of desired form.

an ur process can be usefully employed also in the manufacture of other articles, as valve tappets for engines, of which one portion only is submitted to considerable stresses g the use of the high-grade ex nsive meta being limited to this portion. hat we claim is: i w 'A'process for manufacturing" valves more particularly for internal combustion engines lot 

